286 lines
11 KiB
Python
286 lines
11 KiB
Python
# PyTorch utils
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import logging
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import math
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import os
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import time
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from contextlib import contextmanager
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from copy import deepcopy
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import torch
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import torch.backends.cudnn as cudnn
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import torch.nn as nn
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import torch.nn.functional as F
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import torchvision
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try:
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import thop # for FLOPS computation
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except ImportError:
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thop = None
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logger = logging.getLogger(__name__)
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@contextmanager
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def torch_distributed_zero_first(local_rank: int):
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"""
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Decorator to make all processes in distributed training wait for each local_master to do something.
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"""
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if local_rank not in [-1, 0]:
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torch.distributed.barrier()
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yield
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if local_rank == 0:
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torch.distributed.barrier()
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def init_torch_seeds(seed=0):
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# Speed-reproducibility tradeoff https://pytorch.org/docs/stable/notes/randomness.html
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torch.manual_seed(seed)
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if seed == 0: # slower, more reproducible
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cudnn.benchmark, cudnn.deterministic = False, True
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else: # faster, less reproducible
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cudnn.benchmark, cudnn.deterministic = True, False
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def select_device(device='', batch_size=None):
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# device = 'cpu' or '0' or '0,1,2,3'
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s = f'Using torch {torch.__version__} ' # string
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cpu = device.lower() == 'cpu'
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if cpu:
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os.environ['CUDA_VISIBLE_DEVICES'] = '-1' # force torch.cuda.is_available() = False
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elif device: # non-cpu device requested
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os.environ['CUDA_VISIBLE_DEVICES'] = device # set environment variable
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assert torch.cuda.is_available(), f'CUDA unavailable, invalid device {device} requested' # check availability
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cuda = torch.cuda.is_available() and not cpu
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if cuda:
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n = torch.cuda.device_count()
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if n > 1 and batch_size: # check that batch_size is compatible with device_count
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assert batch_size % n == 0, f'batch-size {batch_size} not multiple of GPU count {n}'
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space = ' ' * len(s)
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for i, d in enumerate(device.split(',') if device else range(n)):
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p = torch.cuda.get_device_properties(i)
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s += f"{'' if i == 0 else space}CUDA:{d} ({p.name}, {p.total_memory / 1024 ** 2}MB)\n" # bytes to MB
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else:
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s += 'CPU'
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logger.info(f'{s}\n') # skip a line
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return torch.device('cuda:0' if cuda else 'cpu')
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def time_synchronized():
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# pytorch-accurate time
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if torch.cuda.is_available():
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torch.cuda.synchronize()
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return time.time()
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def profile(x, ops, n=100, device=None):
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# profile a pytorch module or list of modules. Example usage:
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# x = torch.randn(16, 3, 640, 640) # input
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# m1 = lambda x: x * torch.sigmoid(x)
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# m2 = nn.SiLU()
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# profile(x, [m1, m2], n=100) # profile speed over 100 iterations
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device = device or torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
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x = x.to(device)
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x.requires_grad = True
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print(torch.__version__, device.type, torch.cuda.get_device_properties(0) if device.type == 'cuda' else '')
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print(f"\n{'Params':>12s}{'GFLOPS':>12s}{'forward (ms)':>16s}{'backward (ms)':>16s}{'input':>24s}{'output':>24s}")
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for m in ops if isinstance(ops, list) else [ops]:
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m = m.to(device) if hasattr(m, 'to') else m # device
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m = m.half() if hasattr(m, 'half') and isinstance(x, torch.Tensor) and x.dtype is torch.float16 else m # type
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dtf, dtb, t = 0., 0., [0., 0., 0.] # dt forward, backward
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try:
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flops = thop.profile(m, inputs=(x,), verbose=False)[0] / 1E9 * 2 # GFLOPS
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except:
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flops = 0
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for _ in range(n):
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t[0] = time_synchronized()
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y = m(x)
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t[1] = time_synchronized()
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try:
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_ = y.sum().backward()
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t[2] = time_synchronized()
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except: # no backward method
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t[2] = float('nan')
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dtf += (t[1] - t[0]) * 1000 / n # ms per op forward
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dtb += (t[2] - t[1]) * 1000 / n # ms per op backward
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s_in = tuple(x.shape) if isinstance(x, torch.Tensor) else 'list'
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s_out = tuple(y.shape) if isinstance(y, torch.Tensor) else 'list'
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p = sum(list(x.numel() for x in m.parameters())) if isinstance(m, nn.Module) else 0 # parameters
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print(f'{p:12.4g}{flops:12.4g}{dtf:16.4g}{dtb:16.4g}{str(s_in):>24s}{str(s_out):>24s}')
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def is_parallel(model):
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return type(model) in (nn.parallel.DataParallel, nn.parallel.DistributedDataParallel)
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def intersect_dicts(da, db, exclude=()):
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# Dictionary intersection of matching keys and shapes, omitting 'exclude' keys, using da values
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return {k: v for k, v in da.items() if k in db and not any(x in k for x in exclude) and v.shape == db[k].shape}
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def initialize_weights(model):
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for m in model.modules():
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t = type(m)
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if t is nn.Conv2d:
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pass # nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
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elif t is nn.BatchNorm2d:
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m.eps = 1e-3
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m.momentum = 0.03
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elif t in [nn.Hardswish, nn.LeakyReLU, nn.ReLU, nn.ReLU6]:
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m.inplace = True
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def find_modules(model, mclass=nn.Conv2d):
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# Finds layer indices matching module class 'mclass'
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return [i for i, m in enumerate(model.module_list) if isinstance(m, mclass)]
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def sparsity(model):
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# Return global model sparsity
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a, b = 0., 0.
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for p in model.parameters():
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a += p.numel()
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b += (p == 0).sum()
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return b / a
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def prune(model, amount=0.3):
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# Prune model to requested global sparsity
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import torch.nn.utils.prune as prune
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print('Pruning model... ', end='')
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for name, m in model.named_modules():
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if isinstance(m, nn.Conv2d):
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prune.l1_unstructured(m, name='weight', amount=amount) # prune
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prune.remove(m, 'weight') # make permanent
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print(' %.3g global sparsity' % sparsity(model))
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def fuse_conv_and_bn(conv, bn):
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# Fuse convolution and batchnorm layers https://tehnokv.com/posts/fusing-batchnorm-and-conv/
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fusedconv = nn.Conv2d(conv.in_channels,
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conv.out_channels,
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kernel_size=conv.kernel_size,
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stride=conv.stride,
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padding=conv.padding,
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groups=conv.groups,
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bias=True).requires_grad_(False).to(conv.weight.device)
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# prepare filters
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w_conv = conv.weight.clone().view(conv.out_channels, -1)
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w_bn = torch.diag(bn.weight.div(torch.sqrt(bn.eps + bn.running_var)))
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fusedconv.weight.copy_(torch.mm(w_bn, w_conv).view(fusedconv.weight.size()))
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# prepare spatial bias
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b_conv = torch.zeros(conv.weight.size(0), device=conv.weight.device) if conv.bias is None else conv.bias
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b_bn = bn.bias - bn.weight.mul(bn.running_mean).div(torch.sqrt(bn.running_var + bn.eps))
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fusedconv.bias.copy_(torch.mm(w_bn, b_conv.reshape(-1, 1)).reshape(-1) + b_bn)
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return fusedconv
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def model_info(model, verbose=False, img_size=640):
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# Model information. img_size may be int or list, i.e. img_size=640 or img_size=[640, 320]
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n_p = sum(x.numel() for x in model.parameters()) # number parameters
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n_g = sum(x.numel() for x in model.parameters() if x.requires_grad) # number gradients
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if verbose:
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print('%5s %40s %9s %12s %20s %10s %10s' % ('layer', 'name', 'gradient', 'parameters', 'shape', 'mu', 'sigma'))
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for i, (name, p) in enumerate(model.named_parameters()):
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name = name.replace('module_list.', '')
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print('%5g %40s %9s %12g %20s %10.3g %10.3g' %
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(i, name, p.requires_grad, p.numel(), list(p.shape), p.mean(), p.std()))
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try: # FLOPS
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from thop import profile
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stride = int(model.stride.max()) if hasattr(model, 'stride') else 32
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img = torch.zeros((1, model.yaml.get('ch', 3), stride, stride), device=next(model.parameters()).device) # input
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flops = profile(deepcopy(model), inputs=(img,), verbose=False)[0] / 1E9 * 2 # stride GFLOPS
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img_size = img_size if isinstance(img_size, list) else [img_size, img_size] # expand if int/float
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fs = ', %.1f GFLOPS' % (flops * img_size[0] / stride * img_size[1] / stride) # 640x640 GFLOPS
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except (ImportError, Exception):
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fs = ''
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logger.info(f"Model Summary: {len(list(model.modules()))} layers, {n_p} parameters, {n_g} gradients{fs}")
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def load_classifier(name='resnet101', n=2):
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# Loads a pretrained model reshaped to n-class output
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model = torchvision.models.__dict__[name](pretrained=True)
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# ResNet model properties
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# input_size = [3, 224, 224]
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# input_space = 'RGB'
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# input_range = [0, 1]
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# mean = [0.485, 0.456, 0.406]
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# std = [0.229, 0.224, 0.225]
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# Reshape output to n classes
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filters = model.fc.weight.shape[1]
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model.fc.bias = nn.Parameter(torch.zeros(n), requires_grad=True)
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model.fc.weight = nn.Parameter(torch.zeros(n, filters), requires_grad=True)
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model.fc.out_features = n
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return model
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def scale_img(img, ratio=1.0, same_shape=False): # img(16,3,256,416), r=ratio
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# scales img(bs,3,y,x) by ratio
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if ratio == 1.0:
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return img
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else:
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h, w = img.shape[2:]
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s = (int(h * ratio), int(w * ratio)) # new size
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img = F.interpolate(img, size=s, mode='bilinear', align_corners=False) # resize
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if not same_shape: # pad/crop img
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gs = 32 # (pixels) grid size
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h, w = [math.ceil(x * ratio / gs) * gs for x in (h, w)]
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return F.pad(img, [0, w - s[1], 0, h - s[0]], value=0.447) # value = imagenet mean
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def copy_attr(a, b, include=(), exclude=()):
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# Copy attributes from b to a, options to only include [...] and to exclude [...]
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for k, v in b.__dict__.items():
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if (len(include) and k not in include) or k.startswith('_') or k in exclude:
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continue
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else:
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setattr(a, k, v)
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class ModelEMA:
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""" Model Exponential Moving Average from https://github.com/rwightman/pytorch-image-models
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Keep a moving average of everything in the model state_dict (parameters and buffers).
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This is intended to allow functionality like
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https://www.tensorflow.org/api_docs/python/tf/train/ExponentialMovingAverage
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A smoothed version of the weights is necessary for some training schemes to perform well.
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This class is sensitive where it is initialized in the sequence of model init,
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GPU assignment and distributed training wrappers.
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"""
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def __init__(self, model, decay=0.9999, updates=0):
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# Create EMA
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self.ema = deepcopy(model.module if is_parallel(model) else model).eval() # FP32 EMA
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# if next(model.parameters()).device.type != 'cpu':
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# self.ema.half() # FP16 EMA
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self.updates = updates # number of EMA updates
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self.decay = lambda x: decay * (1 - math.exp(-x / 2000)) # decay exponential ramp (to help early epochs)
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for p in self.ema.parameters():
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p.requires_grad_(False)
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def update(self, model):
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# Update EMA parameters
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with torch.no_grad():
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self.updates += 1
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d = self.decay(self.updates)
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msd = model.module.state_dict() if is_parallel(model) else model.state_dict() # model state_dict
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for k, v in self.ema.state_dict().items():
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if v.dtype.is_floating_point:
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v *= d
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v += (1. - d) * msd[k].detach()
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def update_attr(self, model, include=(), exclude=('process_group', 'reducer')):
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# Update EMA attributes
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copy_attr(self.ema, model, include, exclude)
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